Electric motor or dynamo



(No Model.)

11.. K. T'HIEL.

ELECTRIC MOTOR 0R DYNAMO. No. 510,102. Patented Dec. 5, 1893 5222922302? jf'rmanffjzzz AAAAAAAAAAAAAAAAAAAAAAAAA OMFANY.

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} UNITED STATES PATENT OFFICE.

HERMAN K. THIEL, OF ALPENA, MICHIGAN.

ELECTRIC MOTOR OR DYNAMO.

SPECIFICATION forming part of Letters Patent No. 510,102, dated December 5, 1893.

Application filed April 10, 1893- Serial No. 469,744. (No model.)

To all whom it may concern:

Be it known that I, HERMAN K. THIEL, a citizen of the United States, residing at Alpena, in the county of Alpena and State of Michigan, have invented a new and useful Improvement in Electric Motors or Dynamos, of which the following is a specification.

My invention relates, particularly, to an improvement in the construction of the fieldmagnets of electric motors and dynamos. I find that by tapering, to a certain maximum degree, the core of the field-magnet toward its end which is presented to the armature, or, in other words, by expanding the core in certain minimum proportion from that end in a backward direction and winding the tapering core without corresponding taper of the wound wire, thus to increase the thickness thereof toward the tapering end of the core, a very much greater efficiency is produced in the matter of electric generation than with any other form of magnet-core known to me, owing to enhanced concentration at the tapered end of the core of the magnetic lines of force.

In the accompanying drawings-Figure 1 is a cross-sectional View of a dynamo provided with my improvement; and Fig. 2, a perspective View of my improved field-magnet core.

A is the frame of the machine, of any known or desired construction.

B is the rotary armature; and C, O are the field-magnets, each comprising a tapering core D, wound with wire D and properly fastened to the frame. As shown in the drawings, and most clearly in Fig. 2, the iron core is of latorally oblong shape and tapers regularly, on its four sides, from the rear end to the end which it presents to the armature, at which it is provided with the thin pole-piece r.

In order that the tapering form of the fieldmagnet core shall be effective in producing such concentration of the lines of magnetic force at the tapering end as will adequately enhance the power of the machine, it is necessary that the surface-areas at the flaring and tapering ends of said core shall be, at least, as three to one, the surface-area at the larger end being, thus, at least three times that at the smaller end; though it may be more, particularly where longer cores, such as those represented, are employed, but it may not be materially less. It is also important that the north and south pole-pieces of the tapering cores should terminate the respective cores adjacent to and at diametrically opposite sides of the armature, and not, as

has hitherto been done, each form a central.

pole-piece common to two separately wound sections of a core extending from opposite sides of the frame and tapering toward the common central pole-piece; since by such connection of two core-sections, the forces generated on eachtend to oppose each other against concentration at the tapered ends, and, consequently, against their free distribution over the expanse of surface of the common pole-piece, whence to be taken up by the armature.

It will further be noticed that while the cores of the field-magnets D taper toward their inner ends, there is no corresponding taper of the wound wire D, the thickness of which increases toward the pole-pieces 0", preferably to the extent shown of rendering the field-magnets cylindrical in form. This increased thickness of the body of wound wire on the tapering core is an important feature in myimprovement, since the increased number of ampere turns thereby afiorded materially increases the concentration of the lines of force at the inner ends of the cores.

What I claim as new, and desire to secure by Letters Patent, is-

1. An electric motor or dynamo, having the cores of its fieldmagnets tapering toward their inner ends presented to the armature and provided with pole-pieces r, the body of wound wire D on each core thickening toward its tapering end, substantially as an for the purpose set forth.

2. An electric motor or dynamo having the tapering field-magnet cores D provided with pole-pieces r and wound with wire D to an extent rendering the magnets externally cylindrical in form, substantially as and for the purpose set forth.

HERMAN K. TI-IIEL.

In presence 0f-- W. E. DEPEW, ALBERT E. MANNING. 

